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A protostar is a very young star that is still gathering mass from its parent molecular cloud. It is the earliest phase in the process of stellar evolution . [ 1 ] For a low-mass star (i.e. that of the Sun or lower), it lasts about 500,000 years. [ 2 ]
A star forms by accumulation of material that falls in to a protostar from a circumstellar disk or envelope. Material in the disk is cooler than the surface of the protostar, so it radiates at longer wavelengths of light producing excess infrared emission. As material in the disk is depleted, the infrared excess decreases.
The protostar at first only has about 1% of its final mass. But the envelope of the star continues to grow as infalling material is accreted. After 10,000–100,000 years, [1] thermonuclear fusion begins in its core, then a strong stellar wind is produced which stops the infall of new mass. The protostar is now considered a young star since its ...
A pre-main-sequence star (also known as a PMS star and PMS object) is a star in the stage when it has not yet reached the main sequence.Earlier in its life, the object is a protostar that grows by acquiring mass from its surrounding envelope of interstellar dust and gas.
The Boomerang Nebula is an excellent example of a bipolar outflow. Image credit: NASA, STScI. A bipolar outflow comprises two continuous flows of gas from the poles of a star.
An astronomical instrument is a device for observing, measuring or recording astronomical data.They are used in the scientific field of astronomy, a natural science that studies celestial objects and the phenomena that occur in the cosmos, with the object of explaining their origin and evolution over time.
The evolutionary sequence of protoplanetary disks with substructures [3] A 2009 image showing fractions of stars that suggest some evidence of having a protoplanetary disk as a function of their stellar age in millions of years; The samples are nearby young clusters and associations.
An HR Diagram of PMS stars with different masses. The Hayashi Track is depicted as vertical lines, while the Henyey are horizontal. Higher mass stars spend very little time on the Hayashi Track, while the lowest mass stars never reach the Heyney Track, with a gradient seen of time spent on each track as the mass increases.